How do I fix the Blazor Server App Login Error

Question

I am trying to log in to my dashboard/page. When I log in it works perfectly fine it returns a token but when I Deserialze the token I get the error below:

when Im trying to Deserialize my Web Token on this line:

var returnedUser = JsonConvert.DeserializeObject(responseBody);

I get the error below:

Unexpected character encountered while parsing value: s. Path '', line 0, position 0

I am Using Blazor Server App and I'm not really sure where I'm getting it all wrong.

My code is below as well.

@page "/pages/authentication/login"
@layout LoginLayout
@inject HttpClient Http
@inject Blazored.SessionStorage.ISessionStorageService sessionStorage
@inject AuthenticationStateProvider AuthenticationStateProvider
@inject NavigationManager NavigationManager
@using MileApp.Models
@using MileApp.Utilities
@using Newtonsoft.Json


<MudText Typo="Typo.h4" GutterBottom="true" >Sign In</MudText>

<MudText>Don't have an account? <MudLink Href="/pages/authentication/register">Sign Up</MudLink></MudText>

<MudTextField T="string" @bind-Value="@username"  Label="E-mail" Variant="Variant.Outlined" Class="my-6"></MudTextField>

<MudTextField @bind-Value="@Password" Label="Password" Variant="Variant.Outlined" InputType="@PasswordInput" Adornment="Adornment.End" AdornmentIcon="@PasswordInputIcon" OnAdornmentClick="TogglePasswordVisibility" />

<div Class="d-flex justify-space-between align-center">
    <MudCheckBox T="bool" Label="Remember me?" Color="Color.Primary" Class="ml-n1 my-3"></MudCheckBox>
    <MudLink Href="/pages/authentication/forgot-password">Forgot pwd?</MudLink>
</div>


<MudButton Variant="Variant.Filled" Color="Color.Primary"  Size="Size.Large" FullWidth="true" OnClick="@ValidateUser">Sign In</MudButton>

@code {
    string username;
    string Password;
    bool PasswordVisibility;
    InputType PasswordInput = InputType.Password;
    string PasswordInputIcon = Icons.Material.Filled.VisibilityOff;

    

    void TogglePasswordVisibility()
    {
        @if (PasswordVisibility)
        {
            PasswordVisibility = false;
            PasswordInputIcon = Icons.Material.Filled.VisibilityOff;
            PasswordInput = InputType.Password;
        }
        else
        {
            PasswordVisibility = true;
            PasswordInputIcon = Icons.Material.Filled.Visibility;
            PasswordInput = InputType.Text;
        }
    }

    private async Task<bool> ValidateUser()
    {
        UserLogin u = new UserLogin();
        u.username = username;
        u.Password = Password;

        var mydata = u;

        string SerializedUser = JsonConvert.SerializeObject(u);


        HttpRequestMessage httpRequestMessage = new HttpRequestMessage();
        httpRequestMessage.Method = new HttpMethod("POST");
        httpRequestMessage.RequestUri = new Uri("https://localhost:7101/api/Name/authenticate");
        httpRequestMessage.Content = new StringContent(SerializedUser);

        httpRequestMessage.Content.Headers.ContentType = new System.Net.Http.Headers.MediaTypeHeaderValue("application/json");

        var response = await Http.SendAsync(httpRequestMessage);

        var responseStatusCode = response.StatusCode;
        var responseBody = await response.Content.ReadAsStringAsync();
        //string test = $"{responseBody}";

        if(responseStatusCode.ToString() == "OK")
        {
            try
            {

                var returnedUser = JsonConvert.DeserializeObject(responseBody);
            }
            catch(Exception hh)
            {
                string h = hh.Message;
            }

            ((CustomAuthStateProvider)AuthenticationStateProvider).MarkUserAsAuthenticated(u.username);
            NavigationManager.NavigateTo("/home/dashboard");

            await sessionStorage.SetItemAsync("emailAdress", u.username);

            return await Task.FromResult(true);
        }
        else
        {
            return await Task.FromResult(false);
        }
    }
}

namespace MileApp.Models
{
    public class UserLogin
    {
        public string username { get; set; }
        public string Password { get; set; }
    }
}

{
//Web Token looks like this in the response Body when decoded I used JWT.io to decode
  "unique_name": "Aubrey",
  "nbf": 1645513472,
  "exp": 1645515272,
  "iat": 1645513472
}```

Unexpected character encountered while parsing value: s. Path '', line 0, position 0